Error running the project in Play Framework. Failed to listen to port :9000
As you are able to start it using another port, it means that something is really using that port. It may be a different application or a previously stalled start of activator/play.
To find out what is using it you can use for example lsof
in Linux:
$ lsof -i :9000
Once you find its pid you can stop that process.
If that port is used by another service and you really need it, instead of providing always the port to the run
command, you can try to add to your sbtopts (either in ~/.sbtopts
file or SBT_OPTS
env var) this:
-Dhttp.port=9876